PM thanks resigning U.S. Special Envoy for Middle East Peace for his work, saying he regrets the Palestinians' refusal to attend peace talks.

Prime Minister Benjamin Netanyahu spoke to former senator George Mitchell Saturday, after the latter submitted his resignation from his role as U.S. Special Envoy for Middle East Peace, and thanked him for his peace-seeking efforts.

Netanyahu expressed his disappointment in Mitchell's decision to quit, and in the Palestinians' refusal to attend talks that Mitchell worked so hard to advance. The prime minister added that the Palestinians "set countless preconditions that made [Mitchell's] work difficult, and at the end of the process even united with Hamas."

Mitchell submitted his resignation letter on Friday, saying he strongly supports U.S. President Barak Obama's vision for peace.

"I strongly support your vision of comprehensive peace in the Middle East and thank you for giving me the opportunity to be part of your administration," said Mitchell in his resignation letter. "It has been an honor for me to again serve our country."

Mitchell is leaving as peace talks between Israel and the Palestinians have come to a standstill, though he did not mention the matter in his resignation. He said that when he took on the role his intention was to serve for two years and more than that has now passed.

His resignation will be effective May 20 - the same day Prime Minister Benjamin Netanyahu visits the White House.

Both AIPAC and Israel's Ambassador to the United States Michael Oren shared Netanyahu's sentiments regarding both Mitchell and the Palestinians. The lobby group added that Mitchell made it clear to both parties that the only way to "true peace" was via direct, bilateral negotiations."